Objective: The purpose of this in vitro study was to evaluate the effects of 10% carbamide peroxide (Vivastyle/Vivadent) and 6.5% hydrogen peroxide strip bands (Crest Professional Whitestrips) on the surface roughness and hardness of the 3 different tooth-colored restoratives: an ormocer (Definite), a packable composite (Filtek P60), and a flowable composite (Filtek Flow).
Method and Materials: A total of 48 specimens (10 mm in diameter and 2 mm thick) of each material were fabricated against a mylar surface. After being polished with Sof-Lex discs, they were randomly divided into 3 groups of 16 and treated as follows: group I was stored in distilled water at 37°C for 2 weeks (control), group II was treated with Vivastyle for 2 hours per day for 2 weeks, and group III was treated with Whitestrips for 30 minutes twice a day for 2 weeks. For groups II and III, the specimens were stored in distilled water at 37°C during the hiatus period. At the end of the test period, the specimens were first subjected to surface roughness and then to microhardness tests. The data were analyzed by Kruskal-Wallis and Mann-Whitney U tests.
Results: Both bleaching regimens increased the surface roughness of the materials (P < .05), but Whitestrips significantly increased the roughness of materials more than did Vivastyle (P < .05). Both bleaching regimens decreased significantly the hardness of tested materials except Filtek P60 (P < .05).
Conclusion: Bleaching agents may affect the surface of existing restorations; therefore, they should not be used indiscriminately when tooth-colored restorations are present. (Quintessence Int 2007;38:90.e83–87)
Key words: bleaching, hardness, roughness, tooth-colored restorative materials